Color stabilization of ortho-benzyl parachlorphenol

ABSTRACT

THIS INVENTION DISCLOSES A COMPOSITION, COMPRISING ORTHO-BENZYL PARACHLOROPHENOL AND A COLOR STABILIZER THEREFOR. THIS COLOR STABILIZER INCLUDES FROM ABOUT 0.01% TO ABOUT 0.5% THIOUREA AND FROM ABOUT 0.025% TO ABOUT 0.75% OF AN ORGANIC PHOSPHITE BY WEIGHT, BASED UPON ORTHO-BENZYL PARACHLOROPHENOL.

April 11, 1972 COLOR GARDN ER I953 SERIES F. J.- SHELTON 3,655,779

COLOR STABILIZATION 0F ORTHO-BENZYL PARACHLORPHENOL Filed Oct. 29, 19680.05 wt.% Thioureo l6- OJOO vn. Triphenyl Phosphiie COLOR STABILITY VSEXPOSURE DAYS 0.050 V". Thioureo +0. I00 wt. Triphenyl Phosphite o r I II l I 0 2O 4O 60 80 I00 EXPOSURE DAYS INVENTOR.

F rcderic J. Shelton ATTORNEY United States Patent 3,655,779 COLORSTABILIZATION 0F ORTHO-BENZYL PARACHLORPHENOL Frederic J. Shelton,Tacoma, Wash., assignor to Reichhold Chemicals, Inc., White Plains, N.Y.Filed Oct. 29, 1968, Ser. No. 771,594 Int. Cl. C07c 37/22 US. Cl. 260619R 1 Claim ABSTRACT OF THE DISCLOSURE This invention discloses acomposition, comprising ortho-benzyl parachlorophenol and a colorstabilizer therefor. This color stabilizer includes from about 0.01% toabout 0.5% thiourea and from about 0.025% to about 0.75% of an organicphosphite by weight, based upon ortho-benzyl parachlorophenol.

This invention relates to the stabilization of the color of ortho-benzylparachlorophenol and its solutions in isopropanol.

The stabilization of color in phenolic compounds has been a problem oflong standing. It has been a particular problem to stabilize the colorof ortho-benzyl parachlorophenol. Solid ortho-benzyl para-chlorophenolor alcoholic solutions of ortho-beuzyl para-chlorophenol when subjectedto light tend to darken in color. The color developed is dependent uponthe types of trace ions present and ranges from rose-pink to dark brown.Unprotected orthobenzyl parachlorophenol, when subjected to light willshow a marked darkening in color in a matter of only a few days exposureto light.

In the quest to find a satisfactory color stabilizer for ortho-benzylparachlorophenol, many compounds were tried which act as colorstabilizers for other organics and it was found that for one reason oranother they were unsatisfactory. Either they did not stabilize thecolor, or the quantity required to achieve color stabilization was fargreater than could be tolerated as a minor constituent in technicalgrade ortho-benzyl parachlorophenol.

The uses for ortho-benzyl para-chlorophenol are many and varied. Onemajor industrial use is as an ingredient for household germicides. Suchhousehold germicide formulations are in many cases sold on the basis ofeach manufacturer having his own distinctive color. It is thereforeexceedingly important that the ortho-benzyl parachlorophenol should notchange color and thereby change the color of the final formulation.

Ortho-benzyl parachlorophenol is also used as dyeing assistant and insuch an application it is vitally important that the ortho-benzylparachlorophenol does not produce the color shift.

It is therefore an object of this invention to provide a stabilizer forortho-benzyl para-chlorophenol which pre vents the darkening in color onprolonged standing.

Another object of this invention is to provide a stabilizer forortho-benzyl para-chlorophenol which prevents the darkening in color onexposure to light.

A further object of this invention is to provide a stabilizer foralcoholic solutions of ortho-benzyl parachlorophenol which preventsdarkening in color on exposure to light and prolonged standing.

Additional and further objects and advantages of this invention will beset forth in part in the description that follows and in part will beobvious therefrom or may be learned by practice of this invention, saidobjects being realized and attained by means of the steps, methods,compositions, cambinations and improvements pointed out in the appendedclaims.

To achieve the foregoing objects and in accordance with its purpose asembodied and broadly described, the process of this invention comprisesthe addition of a combination of thourea and an organic phosphite tostabilize ortho-benzyl parachlorophenol. Said ortho-benzyl parachlorophenol could be in a solid state or it could be dissolved in a solvente.g. isopropyl alcohol. The above mentioned components are only slightlyeffective when used individually. However, when combined in proper ratioa very effective stabilization is produced. Thus the original snow-whitecolor of solid ortho-benzyl parachlorophenol or the very light strawyellow color of alcoholic solutions of ortho-benzyl parachlorophenol canbe preserved even on prolonged exposure to bright light.

The use of from about 0.025% to about 0.75% of organic phosphites incombination with an amount of thiourea ranging from about 0.01% to about0.1% was found to impart a very satisfactory degree of colorstabilization. The percentages are expressed in weight percent and arebased on the amounts of ortho-benzyl parachlorophenol used.

While organic phosphites have been suggested in the past as colorstabilizers for plastic resins and are described for instance in US.Pat. 2,564,646 and 2,716,092, nothing has been made known heretofore asto the use of such phosphites in combination with thiourea.

The organic phosphites which are suitable in the stabilizer compositionof the present invention are selected from the class consisting ofsubstituted or unsubstituted aliphatic or aromatic phosphites,containing both alkyl, aryl and alkaryl groups, organohalophosphites andphosphorus halides containing one or two substituted or unsubstitutedalkoxy and/or aryloxy groups bonded to the phosphorus atom. Thesephosphites include trioctyl phosphite, tris (2-chloroethyl) phosphite,tridecyl phosphite, phosphite ester derivatives of glycols, polyethyleneglycols and glycol ethers like tris-dipropylene glycol phosphite and2,4,6 trichlorophenyl bis-dipropyleneglycol phosphite, etc., triphenylphosphite, tri-(o-xenyl) phosphite, di-(ptert-butylphenyl) monophenylphosphite, diphenyl-monoorthochlorophenyl phosphite,di-(nonylphenyl)-mono-2- chlorethyl phosphite,phenyl-di-(B-chloropropyl) phosphite, di-nonylfi-chloropropyl-phosphite, diphenoxychlorophosphorus,octylphenoxydichlorophosphorus, di (nonylphenoxy) dichlorophosphorus,phenoxyoctyloxychlorophosphorus, and the like. The preferred phosphitehowever is the tri-phenylphosphite on account of the outstanding resultsachieved therefrom.

The accompanying drawing serves to illustrate the synergistic effect ofa typical combination of 0.05% thiourea and 0.1% triphenylphosphite,when compared with the corresponding effect activated by the use of0.05% thiourea alone and 0.1% triphenylphosphite alone.

This invention will be further illustrated by description in connectionwith the following specific examples of the practice of it. The ExamplesI and II serve solely to show the effect of exposure to light of aconventional orthobeuzyl parachlorophenol, which has not been colorstabilized.

EXAMPLE I Solid ortho-benzyl parachlorophenol having a freezing point of49.6 C. and containing 99.9% ortho-benzyl parachlorophenol by infra-redanalysis was exposed to north light in a clear glass container. Theoriginal material was nearly snow-white in color. After two daysexposure, a very distinct pink coloration developed. After one weeksexposure, the material was light reddish-brown. After one monthsexposure, it was medium brown and after three months exposure, it hadbecome dark brown in color.

3 EXAMPLE II Days: Color 1 EXAMPLE III A portion of the stock ofortho-benzyl parachlorophenol used in Example I was melted and dividedinto thirteen equal portions. Each molten portion was treated with adifferent level of thiourea and then flaked on a stainless steel plate.The flaked samples were then exposed under the same north lightconditions as Example I. The quantities of thiourea added and the colorchanges noted over a ninety-day period are shown below:

C O L O R Thiourea, Days weight percent 0 2 7 30 90 EXAMPLE IV The sameprocedure was used as in Example III except that triphenyl phosphite wasused as the treating agent. The quantities of triphenyl phosphite andthe color changes as noted over a ninety-day period are shown below:

COLOR 'Iriphenyl phosphite, Days weight percent 0 2 7 90 0.000 White.-.Yellow.... Bufi Brown Brown. a mo do White do .do Do. 0.025 do do Yellowdo Do. 0,050 do do White .do Do. 075 do do do Bufi D0. 0 100 do do do doDo, 0,250 do do do do Do, 0 500 do do do Tan D0. 0,750 do do do TanBuff. 1 one do do do Ivory Tan 1150 do do do do Tan. 1 500 do do do doIvory 1.750 do do do whiten. D0- 2.00 do do do do Do EXAMPLE V The sameprocedure was used as in Example III except that 0.050 weight percentthiourea was added to all samshown below. The color changes noted over aninety-day period were as follows:

COLOR 0.050% thiourea plus thiphenyl Days phosphite weight percent 0 2 730 90 0.000 White. White. Pink.. Purple-brown. Pur le-brown. 0.010....do. ...do do Pink Pin do do Ivory Ivory do do-.. White. White do do doEXAMPLE VI A portion of the stock of solid ortho-benzyl parachlorophenolused in Example I was used to prepare a ortho-benzyl parachlorophenol,25% isopropanol solution. To samples of this solution thiourea was addedin the amounts shown below. Samples were exposed to the same lightconditions as in Example I and color changes as noted over a -day periodwere as follows:

The color is expressed as Gardner 1953 series.

EXAMPLE VII The same procedure and ingredients were used as in ExampleVI except that triphenyl phosphite was used in place of thiourea.Quantities added and color changes noted over a ninety-day period arerecorded below:

The color is expressed as Gardner 1953 891105.

EXAMPLE VIII The same procedure and ingredients were used as in ExampleVI except that 0.050 weight percent thiourea based upon the containedortho-benzyl parachlorophenol ples and triphenyl phosphite was added inthe amounts 75 was added to all samples. Additionally triphenyl phos- 6phite in the amounts shown below were added. The color What is claimedis: changes taking place over a ninety-day period were as 1. Acomposition comprising ortho-benzyl parachlorofollows: phenol and acolor stabilizer therefor, said stabilizer con- COLOR' sistingessentially of (a) about 0.05 thiourea and (b) 5 about 0.05triphenylphosphite, based upon the weight gggfi fiifggfi Days of saidortho-benzyl parachlorophenol. irei tb icem o 2 7 30 90 References Cited3 3 3 f; 10 UNITED STATES PATENTS 1 1 a 6 10 1 2,161,772 6/1939 Carswell260'-621A 1 i 1 1 1 2,727,928 12/1955 Menn et a1. 260621A i i i3,256,346 6/1966 Albert et al. 260-62l A 1 1 1 1 1 1 1 1 1 1 BERNARDHELFIN, Primary Examiner l l i i 3 a 1 1 1 2 a US. Cl. X.R. 1 2 2 3 4252-404 The color is expressed as Gardner 1953 series.

